California’s governor and the mayor of Los Angeles triumphantly touted Dodger Stadium on Friday as a new mass coronavirus vaccination site capable of administering 12,000 shots a day, despite acknowledging they had no idea how many vaccines the state can expect to get from the federal government.

“As soon as we know, we’ll be able to communicate that more fully to members of the public,” Gov. Gavin Newsom said during a news conference at the stadium, following contentions by governors that the Trump administration is walking back supply promises.

Newsom said he and other governors were told earlier this week that a reserve supply of 50 million doses would be distributed. California has been given 3 million doses so far and was anticipating hundreds of thousands more but is now working to confirm those doses are available.

Michael Pratt, a spokesman for the U.S. Department of Health and Human Services, said there has been no reduction in doses shipped to states.

Oregon Gov. Kate Brown said earlier this week that the state was expanding its vaccine eligibility to include people over 65, teachers and child care providers because of what she said were promises about supply. But she said Friday that the state was reversing course since it would not receive anything from the national stockpile “because there is no federal reserve of doses.”

Newsom declined to go further in criticizing federal officials, saying California’s immediate priority is using the doses it has. He set a goal of using nearly 1.5 million doses by Friday and expects the state to meet it.

Los Angeles Mayor Eric Garcetti said there should be enough vaccine to supply Dodger Stadium and other sites around the county for at least next week. But he acknowledged he can’t be certain.

“The national supply isn’t coming, it’s not a problem with the state, it’s not a problem here locally. We simply don’t have the supply coming in,” he said.

UC Davis Health, for example, was recently told by state officials that it wouldn’t get any more doses for a few weeks. But on Friday, hospital officials learned they would get 5,000 next week, spokesman Steve Telliano said.

“It’s truly a moving target that seems to be changing hourly,” he said in an email.

Elsewhere, counties and providers have been getting far fewer doses than they request from the state. Now that some people are eligible for second doses, vaccinators have to be more careful to ensure there is enough supply.

Newsom and other California Democrats expressed hope that communication about vaccine supply will improve when Democrat Joe Biden becomes president on Wednesday, replacing Republican President Donald Trump.

But many local officials from hospitals and county governments are just as frustrated with the state and its ever-changing guidelines. Newsom’s promotion of newly opened mass vaccination sites and his declaration that everyone over 65 is eligible for the vaccine have led to public confusion and greater demand for a scarce resource.

Santa Clara County has set up five sites, including two mass vaccination sites, and ramped up vaccinations to 6,000 people a day. Still, the county of 2 million has not yet been able to inoculate all the health care workers and people over 75 who are part of the state’s initial rollout because supplies are short, officials said.

Federal and state information is changing daily, “and it’s extraordinarily frustrating,” Santa Clara County counsel James Williams said.

Williams said county officials were told a few days ago that the federal government would release vaccine stockpiles that were being held for second doses but learned through news reports Friday — not through official channels — that no such stockpile exists.

Websites for Kaiser Permanente and Sutter Health crashed this week after the governor’s announcement that those over 65 now qualify for the vaccine.

Newsom said he’d been clear when he announced over Facebook that people over 65 are now eligible.

“The purpose was crystal clear, that is, to make sure the guidelines were not barriers and to provide the flexibility with a sense of urgency that’s needed in this moment,” he said.

Dr. Paul Simon, chief science officer for the Los Angeles County Department of Public Health, said without a steady and predictable supply, long-range planning for vaccine distribution is challenging.

The county has administered more than 219,000 first doses and 60,000 second doses, and officials hope to vaccinate 200,000 more health care workers by Jan. 31. There are about 1.3 million seniors 65 and older in the county.

“We don’t need the full supply to begin vaccinating,” Simon said. “But there will be a heck of a lot of frustration if we open it up for that many people and there’s a very little supply of vaccine to serve them.”

Correction: A previous version of this story gave an incorrect last name for Dr. Paul Simon. This post has been updated.